Finishing process for spinning jets



Patented Feb. 7, 1950 PROCESS FOR SPINNINGYJJETS" Samuel A. Mansfield and Clarence EJBlshop. Narrows, Va:, assignors to Celanese llorporation of Americaixa corporation of Delaware No Drawing. Application .April 30, ,1946, SerialNo. 666,181

1 .Claim. (Cl. 204-440.)

This invention relates to the production of stainless steelspinning jets, such as those employed in apparatus. for spinning artificial filamentary'materials; and relates more partic ularly to an improved process for-the production of said "jets wherebythe latter may be produced rapidly ,and'efilciently.

An object of this invention is the provision of an improvedprocess .for the production of stainless steel spinning jets provided with aplurali'ty of fine orificesand employed for the preparation of artificial. filaments by extrusion operations.

Another objectof "this invention isto provide an improved process for the production of stainless vsteel spinning jets whereby asmooth finish and high: polish may be imparted lto all surfaces of said spinning jets includingthe innersurfaces of 'said orifices without the use of ulling or other mechanical polishingaids;

Other. objects of this inventionxwill' appea from the following detailed description.

The processesuemployedffor forming artificial filaments comprise extruding a filament-forming material under pressure through the orifices of a spinning jet, usually formed of metal, such as stainless steel, into. a setting medium, the number of filaments formed corresponding to the number of holes in the jet. The filaments thus formed, which may number from '20 to 120, or more, are then gathered to form a yarnanzd the yarn collected on a bobbin orother suitable support to form a yarn package.- Asidefro-m the attenuating effect produced by stretching the filaments asthey are formed, the denier-or fineness of the individual filaments is largely controlled by the diameter of the orifices in the spinning jet through which the filament-forming material is extruded. The finerthe denier of the individual filaments, thesofter and more pliable is the yarn.

The production of spinning jets containing orifices of the necessary fine diameter requires an extraordinary degree of skill and precision. Although the orifices are so fine that they can hardly be seen by the unaided eye, they must be smoothly bored, of uniform diameter and properly spaced about the face of the jet to avoid contact between the filaments before they are set, i. e. solidified.

Normally, the manufacture of these jets necessitates a sequence 01' delicate operations which include the countersinking and drilling of the orifices followed by a careful manual finishing of the jet faces and orifices. The finishing operations are necessary to remove any burr and 2 topolislrthe'wrifices to a-uniform" size. The fineness of the work and the close tolerances in- 'volved render" the manufacture of these spinn-lng jets a slow and "time-consuming process:

I"h'ave' now found that the manufacture of spinning jets, and especially jetsformed of 1878 stainless steel, employed in the formation of ar tificial filaments by extrusion operations may be efiected more rapidly and satisfactorily and with the'elimination of 'man-ualpoli'shing andfinish ing operations by "subjecting said spinning jets to electrolytic treatment during certain stages in their manufacture: In accordance with the novel process of my invention, said advantageous res sults are obtained ifthe stainless stee1 spinning jets, during various. stages of their. manufacture aremsubjected. to electrolyticwanodic action emplaying moderate current densities while saidjets are immersed in anworganic. solution of animorganic;electrolyte.- The cathode employed dur ingrsaid. treatment preferably comprises stain? less .steel but other suitable metals may also be employed. Most advantageously, the position of the .jet is changed intermittentlyduring the 816C? trolytictreatment. Themotion imparted to the jet comprises rotating the jet intermittently about its vertical axis 'whilethejet is maintained int-.theasameplane. This intermittent turning avoids undue and uneven attacker the metal at the .minute edges of. the holes which causes an undesirable rounding .of the edges. A single rotation through ian angle .of.18.0 is-satisfactory although the .jet maybe rotated several times dfuringgthe polishing operation through a lesser angle, says-45 or for example, to efiect anet rotation of 180 so that amoreuniiorm and satisfactorypolishing isachieveds A smooth, highly polished finish .or surface free of abrasion .lines, even under microscopic examination. is imparted toall. the areas .of .said jets, including the orifices, and, by suitably extending the period'ofsaid electrolytic treatment, the diameter of the orifices provided therein may be enlarged to any predetermined size.

The most advantageous results are obtained, in accordance with our invention, employing an electrolyte comprising orthophosphoric acid hav ing dissolved therein a soluble aliphatic polyhydroxy alcohol of low volatility containing one or more free hydroxy groups. Examples of the aliphatic hydroxy compounds of low volatility which may be employed are glycerine, ethylene glycol, diethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene gly col monomethyl ether, diethylene glycol monoethyl ether and diethylene glycol monobutyl ether. Preferably, the phosphoric acid solution employed in effecting the electrolytic treatment comprises a mixture of ortho-phosphoric acid and glycerine containing from 40 to 50% by volume of 85% ortho-phosphoric acid and from 50 to 60% by volume of glycerine. I

The temperature of the electrolyte during the electrolytic treatment of the stainless steel spinning jets is most advantageously maintained above about 40 C. and may be as high as 125 C., or more. ever when the temperature of the electrolytic bath is at about 80 C. during the treatment of the stainless steel spinning jets.

A voltage of 15 to 20 volts is usually sufficient in order to maintain the desired current density which is preferably at from about 0.1 to 2.0 amperes per square inch. A current density of about 1.5 amperes per square inch is most satisfactory. 1

Surprisingly enough, we have found that the successful treatment of the stainless steel spine ning jets requires a much lower anode-cathode area ratio than heretofore believed practical. In

accordance with our process, We employ a cathode having'an area of only about five times the area of the anode. A cathode area of from fifteen to twenty or even thirty times the area of the anode was usually believed necessary.

In order further to illustrate ourinvention, but without being limited thereto, the following example is given:

Example A spinning jet blank formed of 18/8 stainless steel is countersunk on the inner face thereof at a plurality of points correspondingto the positions at which the jet holes are to be drilled.

The countersunk spinning jet is then placedin an electrolytic bath consisting of 50 parts by volume of glycerirle dissolved in 50 parts by volume of 85% ortho-phosphoric acid maintained at a temperature of 80 C. A stainless steel cathode having about five times th area of the spinning jet is placed in the bath and connected to the spinning jet through anelectrical circuit of which the jet forms the anode. v Employing a suitable generator, the voltage of the circuit is held to about 15 volts and the current density maintained at about 1.5 amperes per square inch of anode. The current is allowed to flow for 20 minutes to effect the desired anodic action so that any burr present is removed. The jet is withdrawn from the electrolytic bath, the jet holes drilled and the gross burr formed is sub stantially buffed 01f. The drill is passed through the hole again. The drilled jet is then again subjected to the anodic electrolytic treatment employing the same voltage and current density.

Optimum results are achieved howvlustration and that many variations may be The drilled spinning jet is maintained in the electrolytic bath for 5 minutes or unti1 the desired anodic action has taken place, the position of the jet being changed during the operation by rotating it through an angle of 180, with the face being maintained however in the same plane. All of the spinning jet surfaces including the bore of the jet orifices are given an extremely smooth, clean finish by this treatment. The

smooth finish thus imparted to all the jet surfaces resists the deposition of foreign matter in the jet orifices when the jet is employed in filament-forming spinning operations.

It is to be understood that the foregoing detailed description is given merely by way of il- ,made therein without departing from the spirit of our invention.

Having described our invention, what we desire to secure by Letters Patent is:

Process for the production of stainless steel spinning jets having an inner face and an outer face and provided with a plurality of line orifices for filament-forming operations, which consists essentially of the steps of forming depressions in the inner face of said jet at those points at which orifices are to be provided, imparting a smooth finish to said inner face .by'subjecting the spinning jet to electrolytic anodic action in an electrolytic bath consisting essentially of 40 to 50% by volume of orthophosphoric acid and 50 to by volume of glycerine employing a current density-of 0.1 to 2.0 amperes per square inch, the temperature of the electrolytic bath being maintained between about 40 C. to about C. during said electrolytic treatment, drill-- ing orifices through the jet faces where the depressions are formed, and again subjecting the drilled jet to electrolytic anodic action in the said electrolytic bath to impart a smooth finish thereto.

' SAMUEL A. MANSFIELD.

CLARENCE E. BISHOP.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 602,306 Cowper-Coles Apr. 12, 1898 1,747,165 Eaton Feb. 18, 1930 2,115,005 Blaut et a1. Apr. 26, 1938" 2,341,555 Jones Feb. 15, 194;

OTHER REFERENCES Transactions of The Electrochemical Socif ety, vol. 78 (1940), pages 265 through 269.

Metal Industry, June 8, 1945, pages 357 through 359. e 

